21690192 has 20 divisors (see below), whose sum is σ = 56033120. Its totient is φ = 7230048.

The previous prime is 21690187. The next prime is 21690199. The reversal of 21690192 is 29109612.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21690199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 225892 + ... + 225987.

It is an arithmetic number, because the mean of its divisors is an integer number (2801656).

Almost surely, 2^21690192 is an apocalyptic number.

It is an amenable number.

21690192 is an abundant number, since it is smaller than the sum of its proper divisors (34342928).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21690192 is a wasteful number, since it uses less digits than its factorization.

21690192 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451890 (or 451884 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 21690192 is about 4657.2730218444. The cubic root of 21690192 is about 278.8824159901.

The spelling of 21690192 in words is "twenty-one million, six hundred ninety thousand, one hundred ninety-two".